I'm attempting to install a 1500W water heater element into my plastic cooler HLT for e-HERMS. The way I current have it installed is I cut a 1.25 inch hole in the bottom of the cooler and pushed the element through from the bottom. On the bottom between the element 'lip' and the cooler is a silicone gasket, on top is a 1.25 inch stainless steel lock nut applying pressure to the gasket underneath. My first question is this: the water heater element threads are in contact with the cooler 'floor/bottom' - do the threads get plastic melting hot? How does my installation sound so far? more to come...

__________________RootVonRoot Cellars
Let's drink a few and trade a few and fall over, whatdya say?

I have a (very long) 5500W element ran through the side of my cooler without any leakage/issues at all, so it is possible. Wouldn't see why yours couldn't seal up since mine has more strain on it due to gravity and it being horizontal.

Is the surface you seal to nice and flat? Just the o-ring on the outside ought to be enough.

The other question you had: No i have no issues with the heat of the element and the plastic of the cooler. Highest temp i have had so far was in excess of 190F

I just built my second cooler with a heating element. I just blew the first one when I tested out my new contol panel (turned it on with no water, blew in seconds). Anyway, I had problems with sealing my first cooler. I tried every combo including gaskets on either side, both sides, no sides, etc, but it still leaked. I ended up re-enforcing it with aquarium safe silicone. Had very little leakage after that.

So, my second attempt has been a success so far. Drilled a hole small enough that I had to screw the element into the plastic. I added a gasket to the exterior side and put some tape dope on the interior threads and tightened it with the nut. So far, no leaks and I didn't have to add any silicone to seal. Not sure why this one went better, but wanted to share my experiences.